Black mesa problem with ".del" button

every time i press .del button every npc or doors will dissapear and it start of game i fell off from cabin, how do i turn it off? i tried to change by binding but it does nothing, please help

+1.
Stuck in Zoom mode, tried everything. Was surprised to see people disappear when I hit the NumPad period.

Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valveā€™s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.